When officers of a national, international or intermediate labor organization are elected at a convention of delegates who have been chosen by secret ballot, the structure of representation of the membership is a matter for the union to determine in accordance with its constitution and bylaws. There is no indication that Congress intended, in enacting title IV of the Act, to require representation in delegate bodies of labor organizations to reflect the proportionate number of members in each subordinate labor organization represented in such bodies. Questions of such proportionate representation are determined in accordance with the labor organization's constitution and bylaws insofar as they are not inconsistent with the election provisions of the Act. Congress did not attempt to specify the organizational structure or the system of representation which unions must adopt. However, all members must be represented; the union may not deny representation to locals below a certain size.